Angular magnifiction=


=focal length of object lens=20m

focal length of eye lens=1.90 m
so magnification=m=20/1.9=?
Answer:
(a) Magnetic force 
(b) Acceleration 
(C) Speed will remain same
Explanation:
We have given velocity of alpha particle v = 520 m/sec
Magnetic field B = 0.034 T
Charge on alpha particle 
Mass of alpha particle 
Angle between velocity and magnetic field 43°
(a) Force acting on the particle is equal to



(B) According to newton's law
F = ma. here m is mass and a is acceleration.
So acceleration

(c) As the magnetic force is always perpendicular to velocity so speed will remain same neither decreases nor increases.
Maybe there are some situations where speeds depend on wavelengths.
I don't know, and I can't say for sure that there aren't any at all.
But at least in the cases of electromagnetic waves and sound in air,
speeds don't depend on wavelength. All wavelengths of sound have
the same speed in air, and all electromagnetic wavelengths ... like heat,
radio, visible light, X-rays etc. ... have the same speed in vacuum.
If your wave is sound in air at sea level, then its speed is about 340 m/s .
If it's a radio wave, then its speed is about 300 million m/s .
Answer:
light is an example of a wave that is not mechanical .
it is different as it does not need material medium for its propagation
Answer:
the velocity component parallel to the magnetic field vector
Explanation:
When a charged particle moves in a helical path, we can decompose its velocity into two parts v_parallel and v_perpendicular to the magnetic field.
Let's analyze which component receives a force
F = q vxB
the bold letters indicate vectors, in the vector product if the two vectors are parallel the angle is zero and the sin 0 = 0 for which there is no force. therefore the velocity parallel to the field remains constant
If the two vectors are perpendicular, the angle is 90º and the sin 90 = 1, for which there is a force, which has a radial direction and consequently a centripetal acceleration that gives a circular path that does not remove the particle from the magnetic field
When checking the different answers, the correct one is: the velocity component parallel to the magnetic field vector